/*
 * 
 * Copyright 2011 visual-analysis-of-cancer.
 * This file is part of visual-analysis-of-cancer.
 * 
 * visual-analysis-of-cancer is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * visual-analysis-of-cancer is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with kOSMik.  If not, see <http://www.gnu.org/licenses/>.
 *  
 * visual-analysis-of-cancer:
 * An tool to analye the WHO and GLOBOCAN cancer data.
 * http://code.google.com/p/visual-analysis-of-cancer/
 * 
 * 
 * 
 * Authors: Erik Sniegula, Johannes Dahlke
 * 
 * Module:  Programming in Processing for Visual Analytics
 * Group:   20
 * 
 * Created: Aug. 2011
 * Version: 1.0
 *
 */
 




package de.fuberlin.processing.who.cancer.data;

import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.SQLException;

import de.fuberlin.processing.who.cancer.utils.Test;


public class Database {

	static DatabaseConnector dbConnector = null;

	
	private Database() {
		// TODO Auto-generated constructor stub
	}
	
	/**
	 * DatabaseConnector returns the database object for db access. Insofar as yet
	 * no connection to the database is exists, one is made.
	 * 
	 * @return the object that implements the DatabaseConnector interface.
	 * @throws DBException
	 */
	public static DatabaseConnector get() throws DBException {
		if ( Test.isUnassigned( dbConnector)) {
			try {
				dbConnector = new DatabaseConnectorImpl();
			} catch ( DBException e) {
				throw new DBException( "Cannot establish database connection.");
			}
		}
		return dbConnector;
	}


	public static void disconnect() {
		if ( Test.isAssigned( dbConnector)) {
			dbConnector.disconnect();
			dbConnector = null;
		}
	}

}
